Back spacer for typewriters



Aug. 23,1927. 1,640,123

- 0. A. HQKANSON ET AL BACK SPACER FOR TYPEWRITERS Filed Nov. 1925 2 Sheets-Sheet 1 Jurerzt'or;

a Ma (Q? WW ar /6 8 1,640,123 1927' o. A. HOKANSON ET AL BACK SPACER FOR TYPEWRITERS Filed Nov. 6, 1925 2 Sheets-Sheet 2 claims.

Patented Aug. 23, 1927.

UNITED STATES PATENT, OFFICE.

o'rro A. HOKANSON AND JAMES F. xocA, or woons'rocx, ILLINOIS, ASSIGNORS 'ro woonsrrocx'ryrnwm'rna COMPANY, 01 woons'rocx, ILLINOIS, A CORPORATION OF ILLINOIS.

Application filed Kovember This invention relates to mechanism for feeding the platen carriage backwardly by. letter space steps, the mechanism being power actuated.

The object of the invention is to provide mechanism of the gclass described which shall be controlled by a back space key, but which shall be actuated from power mechanism. p

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended In the drawings-' Fig. 1 is afragmentary elevation of a typewriter having one embodiment of the present invention applied thereto;

Fig. 2 is a rear view of the mechanism shown in Fig. 1'; and

Fig. 3 is a fragmentary view showing a detail. I

The numeral designates the frame of a typewriter provided with the usual platen carriage and escapement mechanism, the platen carriage having a rack 11' by which its movement is controlled. A back spacing dog 12 is arranged to engage the teeth of the rack 11, the dog being pivoted on a swinging arm 13. In the position shown in Fig. 2 the back space dog 12 engages the edge of a slot 14 and is held out of engagement with the rack. WVhen the arm 13 swings in a counterclockwise direction, as viewed in Fig. 2, the spring 15 will swing the dog 12 into engagement with the rack teeth and the rotation of the dog about its pivot 16 will be limited by a stop 17. Further movement of the swinging arm will impart a letter space movement to the rack 11 in a backward direction. The arm 13 is pivoted at 18 on the frame of the typewriter and is connected by a link 19 to an arm 20 secured to a rock shaft 21. The rock shaft 21 carries an arm 22 which is provided with a sliding pivotal connection 23 with one arm 24 of a bell crank lever pivoted at 25 on the frame of the machine. The other arm 26 of the bell crank lever is pivoted at 27 to a plunger 28 arranged to be operated by a solenoid 29. A conductor 30 of the solenoid 29 is electrically connected through alever 31 to a, contact point 32. The contact point 32 cooperates w'itha stationary contact point 33 BACK SPACER FOR TYPEWRITERS.

6, 1925. Serial N0. 67,197.

mounted on an insulating block 34 on the frame of the machine 10. The lever 31 has an upwardly projecting arm 35 having 9. lug 36 thereon which engages a lug 37 on a detent 38.- -The detent 38 is secured to a rock shaft 39 pivoted in the frame of the machine. A spring 40 connects the detent 38 and the lever 31 tending to move the contacts 32' and 33 together about the pivotal support 41 of the lever 31. The shaft 39, as shown in Fig. 3, carries an arm 42 on the inner side of the frame 10,

the arm having a pin 43 thereon engaged by A a hook 44 projecting upwardly from the back spacelever 45. The spring 40 tends to rotate the shaft 39 so as to hold the'pin 43 against the hook 44. When the back space lever is depressed the shaft 39 will berocked to move the lug 37 past the shoulder 36 and permit the lever 31 to be moved by the spring 40 to make connection between the contacts 32 and 33. This will permit current to flow through the contacts 32 and 33 andthe solenoid 29 to energize the solenoid. The. plunger 28 will be drawn upwardly moving the bell crank lever 24, 26 and the rock shaft 21, which in turn will raise the linkl19- and the arms13 to operate the back space dog 12. The bell crank arm 26 hasan. adjustable extension '46 which underlies a pin 47 on the lever arm 31. As the plunger 28 reaches its uppermost position, shown in Fig. 1, the extension 46 will raise the lever 31 and disconnect the contacts 32 and 33, thus breaking the circuit.

Means is provided for locking the lever 31 in its disconnected position when raised at the end of the movement of the plunger 28. This means comprises a slide 48 mounted on the upper end 35 of the lever 31 and urged upwardly by a spring 49. When the rock shaft 39 is moved by the back space lever the lug 37 will engage a shoulder 50 on the slide 48 and tension the spring 49. When the lever 31 is moved at the close of the operation of the solenoid 29 it will be rocked sufliciently past the'position shown in Fig. 1 to permit the lug 37 to engage the face 51 of the shoulder 50 and retain the lever 31 in its retracted position until the back space lever is released. As soon as this lever is released. the lug 37 will move from the shoulder onto the shoulder 36 to retain the contact 32 out of engagement with the contact 33. It will thus be seen that depression of the back spacekey will closethe circuit to energize the solenoid 29 and effect a singie back space movement of the pl-atencarriage. The operation of-the solenoid;automatically breaks the circuitby which it is energized after the single back space movement and the lockingmechanism connected with the contacts automatically retains the contacts in oaen position.

e claim 1. The combination with back space mechanism 'for a typewriter, of an electromagnet having a plunger, vmeans operated by said plunger for efi'ecting -a backward letter space movement or saidback space mechanism when-said plunger'is moved by said magnet, a pair of contacts for controlling the circuit of said magnet, aspring tending to close said contacts, a detent for holding saidcontacts open, and a back space lever=for releasing said detent.

2."The combination with back space mechanism for a typewriter, of a solenoid having a plunge-r for actuating said'back space mechanism, a pair of contacts for controlling the circuit of said solenoid, a'spring for closing said contacts, a detent-for'holding said contacts separate, a back space lever for releasing said-detent, means actuated by said plunger for separating said contacts at thecloseof a movement of said plunger, and means for automatically engaging said detent to hold said contacts'in separate position when so moved bysai'd plunger.

3. In a typewriter, the combination with back space mechanism, of a solenoid for actuating saidback space mechanism, a pair of contacts for controlling said solenoid, a back space lever, a detent for holding sai'dacons tacts separate, means operatedby said back space lever for releasing said detent to permit said contacts to be closed to effect op eration ofsai d solenoid, and. means operated vby said solenoid for vseparating; saidcontacts.

4. ln amypewriter, the combination with back space mechanism, of a solenoid having a plunger :fo'r actuating said back space mechanism, a pair of contacts for controlling saidisolenoid, a lever arm forsupporting one o't'saidcontacts, a. detent for engag-- in-g said'levcrarm to holdsaid contacts separated, a fixed and a movable stopon said lever arm for co-operatingwith.said detent, a back space v.key, andmeans controlled by said back space-key for moving said detcnt out ofengagement with said fixed stop and into contact with said movable stop.

5. In .a typewritenthe combination with back space mechanism, of a solenoid-for actuating said mechanism, switch ,mechanism for controlling said solenoid, said switch mechanismcomp-rising .a .movable member having a fixed and a movable stop thereon, detent for ngaging said stops, aback space key=forimovin-g saiddetent from S2llCl'fiXGCl stop into engagement with vsaid movable stop, a spring, :for moving said movable stopinto the path ofsaid detent, and means operated by said solenoid for shifting said movable member into position to release said movable stop and permit said spring to bring said movablestop intot-he path of said detent.

In testimony whereof we have signed our names to this specification on this 2nd day of November A. D. 1925.

OTTO A. HOKANSQN. JAMES :F. *K'OCA. 

